calc find returns incorrect results

I have a list of email addresses which I keep up to date. There are thousands, sorted alphabetically and by number. Since the list is proprietary I really cannot post a screen shot.

Very recently when I hit (CTRL+F) the find box opens and I insert a string to search in the list and the program returns incorrect data. For instance I search the word light and the program selects the following as matches; s_ght, dwight, wright, sleight, and bright.

Now obviously it is returning the ight but not the L. If I search just ight it returns iqht, a few addresses which do not resemble ight in any fashion, iqt.com.au, mauri@yahoo.

I opened a different spreadsheet and the search seemed to work correctly but then I noticed the results were incorrect there also. I searched ‘national’ and it came up as a word but not in a web address; for instance www.firstnational,com was not found even though it was on the screen.

Also all www.whatever.com fields are now blue and though they are not hyperlinks I am told to ctrl+click to follow the link. None of them should be clickable, underlined or blue.

Hello @TheCapnVideo,

Please try in the Find/Replace dialog (CTRL+H), click "Other Options", then uncheck "Similarity search".
HTH, lib

Ok.
When how why is it magically checked?